The process of voting for a host city for the Olympic Games is a study in paradoxes: It's entirely open but very secret.
There are a static number of voters, but that changes from round to round. It's a democratic process, but the would be host cities are not allowed to participate while they're in the running.
Here's how it goes down.
First things first. The 100-plus voting members of the IOC will gather at a hall in the sprawling Bella Center in Copenhagen Friday morning to hear presentations from all four bid cities, along with an official report from their own fact-finding committee.
This is where President and Mrs. Obama, Mayor Daley and Pat Ryan, will make their formal case for hosting the Games. Chicago goes first, then Tokyo, followed by Rio and finally Madrid. This is the formal order which has been followed throughout the process. Chicago has always gone first.
The First Round
At 4:50 in the afternoon, (9:50 Chicago time), the IOC will stage a test vote, to make certain that all of the mechanics are in order. Twenty minutes later, the official vote will begin. And Chicago's bid team will learn whether two years of lobbying and educating and arm-twisting paid off.
"Anyone who tells you today that they know how this is going to turn out, or what voters they have, I think probably they're just guessing," said Chicago 2016's Doug Arnot. "I would say going into this vote, there are probably more undecideds than any recent host city election."
It is at this point, when the voting finally begins, that some of the IOC members must recuse themselves. No nation's members can vote if they have a city in the running. So, on the first round, no IOC members from the United States, Japan, Brazil, or Spain, will be allowed to take part.
That prohibition does not last long.
The Second Round
After the first vote, an electronic tabulation (still secret), will tell the IOC President Jacques Rogge if any city received the required majority (50% plus one vote). If no one achieves that level (and they rarely do), the city with the lowest number of votes is eliminated.
That city's members are then given a voting box, and are allowed to take part in the next round of voting, which begins immediately.
The Third and Fourth Rounds
Once again, unless there is a majority, another city is eliminated. Those delegates are allowed to vote in the third round, when just two cities are left. The IOC President will then announce that a majority has been reached (although he still doesn't know who it is).
At exactly 6:30pm Copenhagen time (11:30am here in Chicago), the IOC will begin a formal television show which it will beam around the world. It's a highly produced, impressive broadcast. And it isn't until the very end, just before noon, Chicago time, that Rogge will open an envelope, and announce a winner.
Everyone immediately adjourns to another room for a news conference where they formally sign the Olympic contract.
Start to finish, from the time Chicago takes the stage, to the announcement, the entire process will take about eleven hours. Eleven, nerve-racking, gut-wrenching hours.
During that time, Chicago will put its best cards on the table, and see everything its opponents are prepared to offer. Ironically, the one thing the city WON'T see is how everyone voted. The totals are revealed, but not the votes of the individual delegates.
Arnot says IOC members can choose to keep their votes secret forever, but no one wants to admit that they backed a loser.
"I maintain that I have never talked to an IOC member after a vote," said Arnot, "who did not vote for the winning city!"
Check out NBCChicago's full coverage of the Olympic Bid here.